congestvpn/TunDevice.cpp

47 lines
1.1 KiB
C++

#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <cstdlib>
#include <cstring>
#include "TunDevice.hpp"
TunDevice::TunDevice(const std::string& dev)
{
struct ifreq ifr;
int fd, err;
if( (fd = open("/dev/net/tun", O_RDWR)) < 0 )
throw TunDevice::InitializationError("Cannot open /dev/net/tun", fd);
memset(&ifr, 0, sizeof(ifr));
/* Flags: IFF_TUN - TUN device (no Ethernet headers)
* IFF_TAP - TAP device
*
* IFF_NO_PI - Do not provide packet information
*/
ifr.ifr_flags = IFF_TUN;
if(!dev.empty()) {
if(dev.size() >= IFNAMSIZ - 2)
throw TunDevice::InitializationError("Device name is too long.");
strncpy(ifr.ifr_name, dev.c_str(), IFNAMSIZ-1);
}
if( (err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ){
close(fd);
throw TunDevice::InitializationError(
"Tunnel interface failed [TUNSETIFF]", err
);
}
_dev_name = ifr.ifr_name;
_fd = fd;
}
TunDevice::~TunDevice() {
close(_fd);
}